Communication systems that are subject to space and weight limitations, such as mobile, manually deployable configurations, often employ (monofilar or bifilar) helical antennas, such as diagrammatically illustrated at 10 in FIG. 1. In order to optimize performance (produce as much gain as possible for a given deployed volume), it is desired that the DC power to radiated RF power efficiency of the radiating system be as high as possible. While this could be accomplished by the use of complex RF power amplifier circuits, the cost of such components is prohibitively expensive. As a consequence, it has been customary practice to use relatively low cost (reduced complexity) RF power amplifiers in the antenna signal feed path. Because such low cost RF amplifier components are also generally low efficiency (e.g., on the order of only fifteen percent) devices, multiple amplifiers are normally operated in parallel, and then summed to provide a combination of their individual amplifying powers.
For this purpose, as diagrammatically shown in FIG. 1, an RF input signal of interest is coupled to a signal splitter 11, which outputs a pair of RF signals to respective (low efficiency) RF amplifiers 12 and 13. The amplified RF signals produced by the RF amplifiers are then recombined or summed in a combiner 14, the output of which is coupled to a single feed port 15 of the helical antenna 10. Unfortunately, because the effect of the combiner 14 is substantial insertion loss, (including that of a signal hybrid, printed circuit board propagation, cabling, etc.) the effective irradiated power of resultant signal applied to the feed port 15 of the helical antenna is substantially below (on the order of one-half to one dB) that produced by the combined effect of the respective RF amplifiers 12 and 13, which degrades the overall power DC power to irradiated power conversion efficiency of the antenna and its RF amplifier feed network.